1a.Objectives (from AD-416):
Develop the potential of entomopathogenic fungi to manage pear thrips, western flower thrips and other major insect pests with soil-dwelling stages, and to encourage the implementation of fungus-based biocontrol methods as part of total IPM approaches for use greenhouse and forest environments against these pests.

1b.Approach (from AD-416):
Utilize entomopathogenic fungi from the University of Vermont (UVM) collection, the ARS Collection of Entomopathogenic Fungal Cultures (ARSEF; Ithaca, NY), and newly isolated strains from greenhouse and field studies to develop improved methods for the use of these fungi in practical programs for the integrated pesticidal and biological control of soil-dwelling stages of western flower thrips and other major insect pests in greenhouses as well as of pear thrips affecting sugar maple trees. The isolation and preservation of new fungal germplasm and co-deposition of old and new UVM isolates in ARSEF remain a major activity. Development of new or improved means and formulations to deliver fungal entomopathogens to control soil-dwelling stages of thrips and other insects in greenhouses is a major concern. Improving the ability of fungal control agents to resist drought and high temperatures with a balanced set of modified formulations and applications approaches is critically important.

3.Progress Report:

Pear thrips populations increased to moderate to high levels in Vermont in 2012. During the summer of 2011, light damage (5 – 10% defoliation) was observed on sugar maple trees in some counties. The overwintering pear thrips populations in the soil were significantly higher in the Fall of 2011 (up to 10 adult thrips per soil sample and a mean of 4 per soil sample) than in the Fall of 2010 (mean of less than 1 per soil sample). Early spring 2012 climatic conditions were ideal for development of leaf damage to sugar maples with a week of early March temperatures between 21-27° C followed by four weeks of normally cool conditions. Sugar maple buds broke in early March and then remained static for several weeks which allowed the early–emerging pear thrips time to feed within the slowly-opening buds resulting in moderate to heavy defoliation of sugar maple across much of Vermont in June 2012 (up to 80% defoliation with a mean of about 20%). A killing frost in mid May in many places combined with the pear thrips damage caused noticeable defoliation to sugar maple trees in all but the most northern counties of Vermont. Some light pear thrips damage was observed on refoliating trees in June 2012.